1. Field of the Invention
This invention relates to the lubrication of wheel bearings in trailers and other vehicles and more particularly, to a bearing lubricating device which is designed to self-lubricate trailer wheel bearings by operation of a springloaded piston located in a cylindrical housing containing a supply of lubricant, such as grease. The bearing lubricating device is characterized by a cylindrically-shaped grease housing, one end of which is open and adapted to fit in the wheel bearing housing of the wheel of a trailer or other vehicle, the open end communicating with a grease chamber located adjacent to the outside wheel bearing. A spring-loaded piston and piston plate combination is located in the grease housing, with the piston plate contacting the supply of grease, in order to bias the grease into contact with the wheel bearings and continually lubricate the wheel bearings as the trailer or other vehicle is operated and the wheels rotate. The free end of the piston projects through an opening in the end of the grease housing and in a first preferred embodiment of the invention, a stop ring is mounted in the housing to arrest the travel of the piston plate and piston and the projecting end of the piston is color-coded to indicate when the supply of grease in the grease housing is sufficient to properly lubricate both the inside and outside wheel bearings. In a second preferred embodiment a piston retainer is fitted over the projecting end of the piston and serves both to limit the travel of the piston inwardly of the bearing lubricating device and to indicate when the supply of grease in the grease housing has reached a sufficiently low level to require recharging of the grease housing. In another preferred embodiment of the invention, a grease fitting is seated in the side of the cylindrical grease housing, for charging the grease housing with grease and in a still further preferred embodiment of the invention, the grease fitting is located in the projecting end of the piston and grease is charged into the grease housing through a longitudinal grease supply passage or bore provided in the piston and communicating with the grease housing.
One of the problems which has long existed in the towing of various types of trailers and similar vehicles is that of failure of the wheel bearings in these trailers and vehicles. Trailers such as boat trailers, utility trailers, cattle trailers and the like, all utilize wheel bearings which must be periodically packed with grease and ultimately replaced, sometimes frequently under circumstances where these trailers are towed long distances. Furthermore, boat trailers are periodically submerged when boats ar launched in lakes and other waterways. Accordingly, the water washes the grease from within the wheel bearing housings, thereby causing the wheel bearings to be improperly lubricated and sometimes ruined, due to the development of friction and excessive heat while the trailer is towed. This circumstance necessitates a lengthy and sometimes expensive repair operation to replace one o both of the inside and outside wheel bearings in each wheel. The bearings must therefore be frequently lubricated, a time-consuming task which requires that the trailer be jacked to free the wheel, the bearing hub and wheel removed and the inside and outside bearings then removed from the bearing housing in the wheel, washed free of old grease, repacked with new grease and replaced in the bearing housing.
2. Description of the Prior Art
Various devices for lubricating wheel bearings and other bearings, as well as warning an operator as to the insufficiency of lubrication of these bearings, are known in the art. L. H. Des Isles U.S. Pat. No. 859,925, dated July 16, 1907, details an "Alarm Signal for Movable Bearings". The device detailed in this patent provides a bell or alarm sounder conveniently mounted directly upon the crank pin, crosshead and like shifting bearings in a machine and so arranged that the bell or alarm sounder will be actuated by the movement of the bearings when the latter become overheated. An "Oiling Device" is detailed in M. E. Brigham U.S. Pat. No. 915,731, dated Mar. 23, 1909, The device includes an oil chamber having multiple outlets from which oil is supplied to different parts of a machine to be lubricated, along with means for supplying the chamber with oil under pressure and control devices for regulating the automatic flow of oil through the outlets in a selected time period. J. T. Leonard U.S. Pat. No. 2,526,568, dated Oct. 17, 1950, details a "Lubricating Apparatus" , which includes a measuring valve that is durable and reliable in operation and may be economically manufactured and adapted for use in a machine, either with grease or with oil as the lubricant. U.S. Pat. No. 2,694,997, dated Nov. 23, 1954, describes a signal device for indicating overheated bearings. The signal device is particularly useful as an indication that the journal bearing of a railroad car has become overheated and is adapted for permanent attachment on the journal axle of the railroad car to accomplish this objective. A "Method and Apparatus for Observing, Indicating and Maintaining Fluid Level" is detailed in Michael R Swearingen U.S. Pat. No. 3,983,958, dated Oct. 5, 1976,. The apparatus is designed for attachment to a bearing housing through an access conduit which provides for observation of the lubricating oil in the bearing housing, thereby ascertaining the level of the oil in the lubricating housing and maintaining a desired fluid level in the bearing. A "Lubricating Device" is detailed in T. G. Kincaid U.S. Pat. No. 960,341, dated June 7, 1910. The Kincaid device is characterized by a grease reservoir adapted to contain a stick of semi-solid lubricant. The reservoir includes a conical bottom which forms an auxiliary grease chamber and panels are provided in the bottom of the reservoir from the lower outer edge of the bottom into the auxiliary chamber at the apex of the cone. A cap is adjustably secured to the reservoir and includes an opening at the top and a spring-press plunger is disposed within the reservoir, with a graduated stem projecting through the opening of the cap and adapted to indicate the quantity of grease contained in the reservoir.
Various types of self-lubricating devices, one of which is marketed under the trademark "Bearing Buddy", are currently used to lubricate the wheel bearings in trailers and similar vehicles. These devices are patterned after the T. G. Kincaid lubricating device and each includes a grease chamber disposed within a cylindrical housing, a spring-loaded plate slidably mounted in the housing and a grease fitting provided in the housing for charging the housing with grease and forcing the spring-loaded plate outwardly. The spring-loaded plate continually exerts pressure against the grease and causes the grease to enter the wheel bearing housing and coat the wheel bearings.
Problems which are characteristic of these self-lubricating devices is the combination of complexity, the lack of facility for quickly determining when the grease housing needs recharging and the difficulty in recharging the grease housing quickly and efficiently, without overcharging. Accordingly, it is an object of this invention to provide a new and improved bearing lubricating device which is capable of self-lubricating the wheel bearings of a trailer or other vehicle by mounting in the vehicle bearing housing, automatically forcing grease from the interior of the bearing lubricating device into the bearing housing to coat the bearings therein and externally indicating when the grease supply in the bearing lubricating device is low.
Another object of the invention is to provide a bearing lubricating device which is capable of being removably mounted in the wheel bearing of trailer or similar vehicle for self-lubricating the wheel bearings therein and indicating the relative quantity of grease located in the device, which bearing lubricating device is characterized by a piston having a color-coded end projecting through the end of the grease-containing housing to indicate the quantity of grease provided in the housing.
A still further object of the invention is to provide a bearing lubricating device for lubricating the wheel bearings in trailers and other vehicles, which device includes a cylindrical, lubricant-containing housing provided with a spring-loaded piston which projects through an opening in the housing, which housing receives a retainer to prevent the piston from recessing in the housing, and further including a grease fitting located in the housing for periodically recharging the housing with lubricant.
Still another object of the invention is to provide a bearing lubricating device which is designed to self-lubricate the wheel bearings of a boat trailer or other vehicle, which bearing lubricating device is characterized by a cylindrical, grease-containing housing provided with spaced air and grease weep holes, respectively, a spring-loaded piston plate and piston slidably disposed in the housing and a grease fitting located in the end of the piston which projects through the end of the grease-containing housing, for periodically charging grease into the housing.
Yet another object of the invention is to provide a new and improved bearing lubricating device for lubricating the inside and outside wheel bearings of a trailer or other vehicle, which device includes a cylindrical housing, one end of which is open and adapted for removable insertion in the bearing housing of the trailer and further including a pair of spaced weep and air expulsion holes, respectively, and a closed end located opposite the open end. A piston extends through an opening provided in the closed end of the grease housing and a round, spring-loaded piston plate is provided on the opposite end of the piston for traversing a segment of the inside chamber of the housing and forcing grease into the bearing housing.